Between 2010 and 2012, we studied the breeding ecology of the common moorhenGallinula chloropus at Lake Tonga, north-east Algeria. Nests were low lying (mean ± SD = 13.64 ± 5.07 cm) and located in tall, dense stands of Scirpus lacustris (72%). The egg-laying period was relatively short, between mid-April and the end of June, peaking in the first half of May. The mean overall clutch size ± SD was 7.03 ± 2.52 (N = 58 clutches) with a slight seasonal downward trend. Rates of successful clutches increased with egg-laying date and water depth mainly due to the seasonal decrease in nest predation and nest flooding. Nest predation, in contrast to nest flooding, was also negatively associated with water depth. The study documented relatively frequent cases of conspecific brood parasitism as well as rarely reported events of interspecific brood parasitism involving the common moorhen both as a host and as a parasite of other avian species.